1. Field of the Invention
The present invention relates to solvent compositions to be used for removing oils and greases attached to articles such as electronic components such as IC, precision mechanical parts, glass substrates, etc., or soil such as flux or dust on printed boards.
2. Discussion of Background
Heretofore, in the precision mechanical industry, the optical instrument industry, the electrical and electronics industry or the plastics industry, for precision cleaning to remove oil, flux, dust, wax or the like attached during manufacturing processes, a hydrochlorofluorocarbon (hereinafter referred to as HCFC) such as dichloropentafluoropropane (hereinafter referred to as R-225) has been widely employed as a fluorinated solvent which is nonflammable and excellent in chemical and heat stability and which is capable of dissolving oils and greases.
However, there is a problem that the ozone depleting potential of HCFC is not 0, and its production is expected to be abolished in advanced countries by year of 2020. Whereas, 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluorohexane (hereinafter sometimes referred to as R52-13) is a fluorinated solvent which has an ozone depleting potential of 0 and which presents little impact to the global environment, but it has a problem that its solvency for oils and greases is low.
Further, an azeotropic mixed solvent composition of 89.2 wt % of R52-13 and 10.8 wt % of methanol (JP-A-7-166199) and an azeotropic mixed solvent composition of 91.1 wt % of R52-13 and 8.9 wt % of ethanol (JP-A-7-166199) are known.
On the other hand, trans-1,2-dichloroethylene (hereinafter sometimes referred to as tDCE) has a high solvency for oils and greases, but it has a problem that its flash point is as low as 4° C.